1 files changed, 47 insertions, 4 deletions

diff --git a/clang/lib/CodeGen/CGRecordLayout.h b/clang/lib/CodeGen/CGRecordLayout.h
index 7581cdbd8f1..d0d8f984a9e 100644
--- a/clang/lib/CodeGen/CGRecordLayout.h
+++ b/clang/lib/CodeGen/CGRecordLayout.h
@@ -10,6 +10,8 @@
 #ifndef CLANG_CODEGEN_CGRECORDLAYOUT_H
 #define CLANG_CODEGEN_CGRECORDLAYOUT_H
 
+#include "llvm/ADT/DenseMap.h"
+#include "clang/AST/Decl.h"
 namespace llvm {
   class Type;
 }
@@ -19,31 +21,72 @@ namespace CodeGen {
 
 /// CGRecordLayout - This class handles struct and union layout info while
 /// lowering AST types to LLVM types.
+///
+/// These layout objects are only created on demand as IR generation requires.
 class CGRecordLayout {
+  friend class CodeGenTypes;
+
   CGRecordLayout(const CGRecordLayout&); // DO NOT IMPLEMENT
   void operator=(const CGRecordLayout&); // DO NOT IMPLEMENT
 
+public:
+  struct BitFieldInfo {
+    BitFieldInfo(unsigned FieldNo,
+                 unsigned Start,
+                 unsigned Size)
+      : FieldNo(FieldNo), Start(Start), Size(Size) {}
+
+    unsigned FieldNo;
+    unsigned Start;
+    unsigned Size;
+  };
+
+private:
   /// The LLVMType corresponding to this record layout.
   const llvm::Type *LLVMType;
 
+  /// Map from (non-bit-field) struct field to the corresponding llvm struct
+  /// type field no. This info is populated by record builder.
+  llvm::DenseMap<const FieldDecl *, unsigned> FieldInfo;
+
+  /// Map from (bit-field) struct field to the corresponding llvm struct type
+  /// field no. This info is populated by record builder.
+  llvm::DenseMap<const FieldDecl *, BitFieldInfo> BitFields;
+
   /// Whether one of the fields in this record layout is a pointer to data
   /// member, or a struct that contains pointer to data member.
-  bool ContainsPointerToDataMember;
+  bool ContainsPointerToDataMember : 1;
 
 public:
   CGRecordLayout(const llvm::Type *T, bool ContainsPointerToDataMember)
     : LLVMType(T), ContainsPointerToDataMember(ContainsPointerToDataMember) {}
 
-  /// getLLVMType - Return llvm type associated with this record.
+  /// \brief Return the LLVM type associated with this record.
   const llvm::Type *getLLVMType() const {
     return LLVMType;
   }
 
-  /// containsPointerToDataMember - Whether this struct contains pointers to
-  /// data members.
+  /// \brief Check whether this struct contains pointers to data members.
   bool containsPointerToDataMember() const {
     return ContainsPointerToDataMember;
   }
+
+  /// \brief Return the BitFieldInfo that corresponds to the field FD.
+  unsigned getLLVMFieldNo(const FieldDecl *FD) const {
+    assert(!FD->isBitField() && "Invalid call for bit-field decl!");
+    assert(FieldInfo.count(FD) && "Invalid field for record!");
+    return FieldInfo.lookup(FD);
+  }
+
+  /// \brief Return llvm::StructType element number that corresponds to the
+  /// field FD.
+  const BitFieldInfo &getBitFieldInfo(const FieldDecl *FD) const {
+    assert(FD->isBitField() && "Invalid call for non bit-field decl!");
+    llvm::DenseMap<const FieldDecl *, BitFieldInfo>::const_iterator
+      it = BitFields.find(FD);
+    assert(it != BitFields.end()  && "Unable to find bitfield info");
+    return it->second;
+  }
 };
 
 }  // end namespace CodeGen